When she died she was buried in Alba Iulia. This might not seem like an important person, she is in fact someone who would do anything to protect her son. As it was, John II Sigismund would abdicate power in Transylvania to the Hapsburgs in 1570 he would become prince of Transylvania. His mother, Isabella died in 1559.
She was at the center of the battle between her husband and the Emperor Ferdinand of Austria, who wanted influence on the people and the Kingdom of Hungary. During this time, she lived in Alba Iulia as well, and the consort of Ferdinand, Anna, was born in Buda ( later a part of Budapest.) Isabella would outlive Anna by 12 years.